Transparent electrodes, which are electrically conductive materials, exhibit excellent light transmission properties, electrical conductivity, and the like, and are therefore used in a wide variety of fields, such as display devices equipped with touch panels. As we have moved towards an ambient information society in recent years, there has been a desire to develop wearable electronic devices which are not restricted by real space and which can be worn on the body.
Indium tin oxide (hereinafter abbreviated in ITO) can be given as an example of an electrically conductive material used in the past in touch panel displays. However, ITO exhibits crystalline film characteristics, and therefore breaks easily. Therefore, in cases where a PET film, for example, is used as a flexible substrate in the use of ITO, the film needs to be thick in order to prevent changes in resistance. In addition, depletion of resources is a problem with indium used in ITO.
Under circumstances such as these, attempts have been made to use metal materials (see Patent Document 1). However, when using a metal to obtain a transparent electrode that exhibits satisfactory light-transmittance, it is essential for the metal layer to be extremely thin. In addition, means have been considered for providing openings in order to achieve light transmission properties. For example, providing openings in an electrode layer of a metal electrode provided with a substrate and a metal electrode layer formed on the surface of the substrate is a known feature. In this type of method, however, it is necessary to use a layer separation mechanism, such as a block copolymer, on the substrate, and such mechanisms are flexible, but are not stretchable and cannot be said to be able to conform to requirements satisfactorily in terms of attachability and ability to follow a variety of shapes.